ccd-cli 1.0.0-alpha.2

Bootstrap and validate Continuous Context Development repositories
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use std::collections::BTreeSet;
use std::convert::TryFrom;
use std::fs;
use std::fs::OpenOptions;
use std::io::{self, Write};
use std::path::{Path, PathBuf};
use std::process;
use std::thread;
use std::time::{Duration, Instant, SystemTime};

use anyhow::{bail, Context, Result};
use rusqlite::Connection;
use serde::{Deserialize, Serialize};
use tracing::debug;

use crate::extensions::backlog_state::{
    self as backlog, BacklogRef, GitHubBacklogCache, GitHubBacklogDispatchView,
};
use crate::paths::state::{ExtensionDispatchStatePaths, StateLayout};

const EXTENSION_DISPATCH_LOCK_FILE: &str = ".extension-dispatch.lock";
const EXTENSION_DISPATCH_LOCK_POLL_MS: u64 = 50;
const EXTENSION_DISPATCH_LOCK_TIMEOUT_MS: u64 = 5_000;
const EXTENSION_DISPATCH_LOCK_STALE_AFTER_SECS: u64 = 60;
const EXTENSION_DISPATCH_DB_SCHEMA_VERSION: u32 = 1;
const EXTENSION_DISPATCH_DB_SCHEMA: &str = r#"
CREATE TABLE IF NOT EXISTS assignments (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    backlog_provider TEXT,
    backlog_kind TEXT,
    backlog_id TEXT,
    backlog_url TEXT NOT NULL DEFAULT '',
    ccd_id INTEGER NOT NULL DEFAULT 0,
    github_issue_number INTEGER NOT NULL DEFAULT 0,
    session_id TEXT NOT NULL DEFAULT '',
    worktree TEXT NOT NULL,
    branch TEXT
);
"#;

#[derive(Debug, Clone, Serialize, PartialEq, Eq)]
pub struct LocalAssignmentView {
    pub backlog_ref: BacklogRef,
    pub ccd_id: u64,
    pub github_issue_number: u64,
    pub title: String,
    pub session_id: String,
    pub branch: Option<String>,
    pub worktree: String,
}

#[derive(Debug, Clone, Serialize)]
pub struct LocalDispatchView {
    pub path: String,
    pub status: &'static str,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub reason: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub dispatch: Option<GitHubBacklogDispatchView>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub assignment: Option<LocalAssignmentView>,
}

pub struct LocalAssignmentRequest<'a> {
    pub session_id: &'a str,
    pub branch: Option<&'a str>,
    pub cache: Option<&'a GitHubBacklogCache>,
    pub cache_status: &'static str,
}

#[derive(Debug, Clone, Deserialize, Serialize, PartialEq, Eq)]
struct DispatchAssignment {
    #[serde(default)]
    backlog_ref: Option<BacklogRef>,
    ccd_id: u64,
    #[serde(default)]
    github_issue_number: u64,
    #[serde(default)]
    session_id: String,
    worktree: String,
    #[serde(default)]
    branch: Option<String>,
}

struct DispatchLock {
    path: PathBuf,
}

impl Drop for DispatchLock {
    fn drop(&mut self) {
        let _ = fs::remove_file(&self.path);
    }
}

#[cfg(any(feature = "extension-backlog", test))]
pub fn load_claimed_ids(paths: &ExtensionDispatchStatePaths) -> Result<BTreeSet<u64>> {
    Ok(load_dispatch_state(paths)?
        .into_iter()
        .filter_map(|assignment| (assignment.ccd_id != 0).then_some(assignment.ccd_id))
        .collect())
}

#[cfg(any(feature = "extension-backlog", test))]
pub fn load_claimed_refs(paths: &ExtensionDispatchStatePaths) -> Result<BTreeSet<String>> {
    Ok(load_dispatch_state(paths)?
        .into_iter()
        .filter_map(|assignment| {
            assignment
                .backlog_ref
                .filter(|backlog_ref| !backlog_ref.is_empty())
                .map(|backlog_ref| backlog_ref.key())
        })
        .collect())
}

pub fn ensure_local_assignment(
    repo_root: &Path,
    layout: &StateLayout,
    locality_id: &str,
    request: LocalAssignmentRequest<'_>,
) -> Result<LocalDispatchView> {
    let LocalAssignmentRequest {
        session_id,
        branch,
        cache,
        cache_status,
    } = request;
    let dispatch_paths = layout.extension_dispatch_state_paths(locality_id)?;
    let dispatch_path = dispatch_paths.primary().to_path_buf();
    let _lock = acquire_dispatch_lock(&dispatch_path)?;
    let mut state = load_dispatch_assignments(&dispatch_paths)?;
    let worktree = repo_root
        .file_name()
        .map(|value| value.to_string_lossy().into_owned())
        .unwrap_or_else(|| repo_root.display().to_string());
    let mut state_changed = false;

    if !session_id.is_empty() {
        let original_len = state.len();
        state.retain(|assignment| !assignment.session_id.is_empty());
        if state.len() != original_len {
            state_changed = true;
        }
    }

    if let Some(cache) = cache {
        if hydrate_assignments_from_cache(&mut state, cache) {
            state_changed = true;
        }

        let original_len = state.len();
        state.retain(|assignment| {
            cache
                .items
                .iter()
                .find(|item| assignment_matches_item(assignment, item))
                .map(|item| item.is_active())
                .unwrap_or(true)
        });
        if state.len() != original_len {
            state_changed = true;
        }
    }

    let existing = find_session_assignment(&state, session_id)
        .or_else(|| branch.and_then(|value| find_branch_assignment(&state, value)));
    if let Some(existing) = existing {
        if state_changed {
            persist_dispatch_state(&dispatch_path, &state)?;
        }
        return Ok(LocalDispatchView {
            path: dispatch_path.display().to_string(),
            status: "existing",
            reason: None,
            dispatch: None,
            assignment: Some(view_for_assignment(existing, cache)),
        });
    }

    if session_id.is_empty() && branch.is_none() {
        if state_changed {
            persist_dispatch_state(&dispatch_path, &state)?;
        }
        return Ok(LocalDispatchView {
            path: dispatch_path.display().to_string(),
            status: "skipped",
            reason: Some("detached HEAD does not allow stable local assignment".to_owned()),
            dispatch: None,
            assignment: None,
        });
    }

    let Some(cache) = cache else {
        if state_changed {
            persist_dispatch_state(&dispatch_path, &state)?;
        }
        return Ok(LocalDispatchView {
            path: dispatch_path.display().to_string(),
            status: "skipped",
            reason: None,
            dispatch: None,
            assignment: None,
        });
    };

    if cache_status == "stale" {
        let claimed_ref_keys = claimed_ref_keys(&state);
        let claimed_ids = claimed_ids(&state);
        if state_changed {
            persist_dispatch_state(&dispatch_path, &state)?;
        }
        return Ok(LocalDispatchView {
            path: dispatch_path.display().to_string(),
            status: "skipped",
            reason: Some("work queue cache is stale".to_owned()),
            dispatch: backlog::dispatch_summary_view(cache, &claimed_ref_keys, &claimed_ids),
            assignment: None,
        });
    }

    let dep_errors = backlog::dep_graph_errors(cache);
    if !dep_errors.is_empty() {
        if state_changed {
            persist_dispatch_state(&dispatch_path, &state)?;
        }
        return Ok(LocalDispatchView {
            path: dispatch_path.display().to_string(),
            status: "skipped",
            reason: Some(format!(
                "work queue has dependency graph errors: {}",
                dep_errors.join("; ")
            )),
            dispatch: None,
            assignment: None,
        });
    }

    let claimed_ref_keys = claimed_ref_keys(&state);
    let claimed_ids = claimed_ids(&state);
    let dispatch = backlog::dispatch_summary_view(cache, &claimed_ref_keys, &claimed_ids);
    let Some(next) = backlog::next_dispatch_item(cache, &claimed_ref_keys, &claimed_ids) else {
        if state_changed {
            persist_dispatch_state(&dispatch_path, &state)?;
        }
        return Ok(LocalDispatchView {
            path: dispatch_path.display().to_string(),
            status: "skipped",
            reason: dispatch
                .as_ref()
                .and_then(|view| view.reason.clone())
                .or_else(|| Some("no ready unclaimed backlog item is available".to_owned())),
            dispatch,
            assignment: None,
        });
    };

    let assignment = DispatchAssignment {
        backlog_ref: (!next.backlog_ref.is_empty()).then_some(next.backlog_ref.clone()),
        ccd_id: next.ccd_id,
        github_issue_number: next.github_issue_number,
        session_id: session_id.to_owned(),
        branch: branch.map(str::to_owned),
        worktree,
    };
    state.push(assignment.clone());
    persist_dispatch_state(&dispatch_path, &state)?;

    Ok(LocalDispatchView {
        path: dispatch_path.display().to_string(),
        status: "assigned",
        reason: None,
        dispatch,
        assignment: Some(view_for_assignment(&assignment, Some(cache))),
    })
}

pub fn ensure_local_assignment_by_branch(
    repo_root: &Path,
    layout: &StateLayout,
    locality_id: &str,
    branch: &str,
    cache: Option<&GitHubBacklogCache>,
    cache_status: &'static str,
) -> Result<LocalDispatchView> {
    ensure_local_assignment(
        repo_root,
        layout,
        locality_id,
        LocalAssignmentRequest {
            session_id: "",
            branch: if branch == "HEAD" { None } else { Some(branch) },
            cache,
            cache_status,
        },
    )
}

pub(crate) fn resolve_branch_assignment(
    layout: &StateLayout,
    locality_id: &str,
    branch: &str,
    cache: Option<&GitHubBacklogCache>,
) -> Result<Option<LocalAssignmentView>> {
    if branch == "HEAD" {
        return Ok(None);
    }

    let dispatch_paths = layout.extension_dispatch_state_paths(locality_id)?;
    let state = load_dispatch_state(&dispatch_paths)?;
    Ok(find_branch_assignment(&state, branch)
        .map(|assignment| view_for_assignment(assignment, cache)))
}

pub fn resolve_session_assignment(
    layout: &StateLayout,
    locality_id: &str,
    session_id: &str,
    cache: Option<&GitHubBacklogCache>,
) -> Result<Option<LocalAssignmentView>> {
    if session_id.is_empty() {
        return Ok(None);
    }
    let dispatch_paths = layout.extension_dispatch_state_paths(locality_id)?;
    let state = load_dispatch_state(&dispatch_paths)?;
    Ok(find_session_assignment(&state, session_id)
        .map(|assignment| view_for_assignment(assignment, cache)))
}

pub fn adopt_unsessioned_entries(
    layout: &StateLayout,
    locality_id: &str,
    session_id: &str,
) -> Result<Vec<LocalAssignmentView>> {
    let dispatch_paths = layout.extension_dispatch_state_paths(locality_id)?;
    adopt_unsessioned_entries_for_paths(&dispatch_paths, session_id)
}

fn adopt_unsessioned_entries_for_paths(
    dispatch_paths: &ExtensionDispatchStatePaths,
    session_id: &str,
) -> Result<Vec<LocalAssignmentView>> {
    let dispatch_path = dispatch_paths.primary().to_path_buf();
    let _lock = acquire_dispatch_lock(&dispatch_path)?;
    let mut state = load_dispatch_assignments(dispatch_paths)?;
    let mut adopted = Vec::new();

    for assignment in &mut state {
        if assignment.session_id.is_empty() {
            assignment.session_id = session_id.to_owned();
            adopted.push(view_for_assignment(assignment, None));
        }
    }

    if !adopted.is_empty() {
        persist_dispatch_state(&dispatch_path, &state)?;
    }

    Ok(adopted)
}

pub fn remove_session_entries(
    layout: &StateLayout,
    locality_id: &str,
    session_id: &str,
) -> Result<()> {
    let dispatch_paths = layout.extension_dispatch_state_paths(locality_id)?;
    remove_session_entries_for_paths(&dispatch_paths, session_id)
}

fn remove_session_entries_for_paths(
    dispatch_paths: &ExtensionDispatchStatePaths,
    session_id: &str,
) -> Result<()> {
    let dispatch_path = dispatch_paths.primary().to_path_buf();
    let _lock = acquire_dispatch_lock(&dispatch_path)?;
    let mut state = load_dispatch_assignments(dispatch_paths)?;
    let original_len = state.len();
    state.retain(|assignment| assignment.session_id != session_id);

    if state.len() != original_len {
        persist_dispatch_state(&dispatch_path, &state)?;
    }

    Ok(())
}

fn load_dispatch_state(paths: &ExtensionDispatchStatePaths) -> Result<Vec<DispatchAssignment>> {
    let dispatch_path = paths.primary().to_path_buf();
    let _lock = acquire_dispatch_lock(&dispatch_path)?;
    load_dispatch_assignments(paths)
}

fn load_dispatch_assignments(
    paths: &ExtensionDispatchStatePaths,
) -> Result<Vec<DispatchAssignment>> {
    match read_dispatch_db(paths.primary())? {
        Some(assignments) => Ok(assignments),
        None => Ok(Vec::new()),
    }
}

fn acquire_dispatch_lock(dispatch_path: &Path) -> Result<DispatchLock> {
    let parent = dispatch_path.parent().ok_or_else(|| {
        anyhow::anyhow!("dispatch path has no parent: {}", dispatch_path.display())
    })?;
    fs::create_dir_all(parent).with_context(|| format!("failed to create {}", parent.display()))?;
    let lock_path = parent.join(EXTENSION_DISPATCH_LOCK_FILE);
    let deadline = Instant::now() + Duration::from_millis(EXTENSION_DISPATCH_LOCK_TIMEOUT_MS);

    loop {
        match create_lock_file(&lock_path) {
            Ok(()) => return Ok(DispatchLock { path: lock_path }),
            Err(error) if error.kind() == io::ErrorKind::AlreadyExists => {
                if Instant::now() >= deadline {
                    if clear_stale_lock(&lock_path)? {
                        continue;
                    }
                    bail!(
                        "backlog dispatch lock is busy at {}; another `ccd start` may still be assigning work in this pod",
                        lock_path.display()
                    );
                }
                thread::sleep(Duration::from_millis(EXTENSION_DISPATCH_LOCK_POLL_MS));
            }
            Err(error) => {
                return Err(error)
                    .with_context(|| format!("failed to acquire {}", lock_path.display()));
            }
        }
    }
}

fn clear_stale_lock(path: &Path) -> Result<bool> {
    let metadata = match fs::metadata(path) {
        Ok(metadata) => metadata,
        Err(error) if error.kind() == io::ErrorKind::NotFound => return Ok(true),
        Err(error) => {
            return Err(error).with_context(|| format!("failed to stat {}", path.display()));
        }
    };
    let modified = metadata
        .modified()
        .with_context(|| format!("failed to read lock mtime for {}", path.display()))?;
    let age = SystemTime::now()
        .duration_since(modified)
        .unwrap_or_default();
    if age < Duration::from_secs(EXTENSION_DISPATCH_LOCK_STALE_AFTER_SECS) {
        return Ok(false);
    }

    fs::remove_file(path).with_context(|| format!("failed to remove {}", path.display()))?;
    Ok(true)
}

fn create_lock_file(path: &Path) -> io::Result<()> {
    let mut file = OpenOptions::new().write(true).create_new(true).open(path)?;
    writeln!(file, "pid={} kind=extension-dispatch", process::id())?;
    file.sync_all()
}

fn find_branch_assignment<'a>(
    assignments: &'a [DispatchAssignment],
    branch: &str,
) -> Option<&'a DispatchAssignment> {
    assignments
        .iter()
        .find(|assignment| assignment.branch.as_deref() == Some(branch))
}

fn find_session_assignment<'a>(
    assignments: &'a [DispatchAssignment],
    session_id: &str,
) -> Option<&'a DispatchAssignment> {
    if session_id.is_empty() {
        return None;
    }
    assignments
        .iter()
        .find(|assignment| assignment.session_id == session_id)
}

fn persist_dispatch_state(dispatch_path: &Path, assignments: &[DispatchAssignment]) -> Result<()> {
    write_dispatch_state(dispatch_path, assignments)
}

fn write_dispatch_state(dispatch_path: &Path, assignments: &[DispatchAssignment]) -> Result<()> {
    debug!(path = %dispatch_path.display(), count = assignments.len(), "writing dispatch state");
    let mut conn = open_dispatch_db(dispatch_path)?;
    let tx = conn.transaction()?;
    tx.execute("DELETE FROM assignments", [])?;

    for assignment in assignments {
        let (backlog_provider, backlog_kind, backlog_id, backlog_url) =
            assignment_backlog_columns(assignment);
        tx.execute(
            "INSERT INTO assignments (
                backlog_provider,
                backlog_kind,
                backlog_id,
                backlog_url,
                ccd_id,
                github_issue_number,
                session_id,
                worktree,
                branch
            ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9)",
            rusqlite::params![
                backlog_provider,
                backlog_kind,
                backlog_id,
                backlog_url,
                i64::try_from(assignment.ccd_id)
                    .with_context(|| format!("ccd_id overflow for {}", dispatch_path.display()))?,
                i64::try_from(assignment.github_issue_number).with_context(|| {
                    format!(
                        "github_issue_number overflow for {}",
                        dispatch_path.display()
                    )
                })?,
                assignment.session_id,
                assignment.worktree,
                assignment.branch,
            ],
        )?;
    }

    tx.commit()?;
    Ok(())
}

fn read_dispatch_db(path: &Path) -> Result<Option<Vec<DispatchAssignment>>> {
    if !path.exists() {
        return Ok(None);
    }

    let conn = open_dispatch_db(path)?;
    let mut stmt = conn.prepare(
        "SELECT backlog_provider, backlog_kind, backlog_id, backlog_url,
                ccd_id, github_issue_number, session_id, worktree, branch
         FROM assignments
         ORDER BY id ASC",
    )?;
    let rows = stmt.query_map([], |row| {
        Ok((
            row.get::<_, Option<String>>(0)?,
            row.get::<_, Option<String>>(1)?,
            row.get::<_, Option<String>>(2)?,
            row.get::<_, String>(3)?,
            row.get::<_, i64>(4)?,
            row.get::<_, i64>(5)?,
            row.get::<_, String>(6)?,
            row.get::<_, String>(7)?,
            row.get::<_, Option<String>>(8)?,
        ))
    })?;
    let mut assignments = Vec::new();
    for row in rows {
        let (
            backlog_provider,
            backlog_kind,
            backlog_id,
            backlog_url,
            ccd_id,
            github_issue_number,
            session_id,
            worktree,
            branch,
        ) = row?;
        let ccd_id = u64::try_from(ccd_id)
            .with_context(|| format!("invalid ccd_id value `{ccd_id}` in {}", path.display()))?;
        let github_issue_number = u64::try_from(github_issue_number).with_context(|| {
            format!(
                "invalid github_issue_number value `{github_issue_number}` in {}",
                path.display()
            )
        })?;
        assignments.push(DispatchAssignment {
            backlog_ref: build_backlog_ref(backlog_provider, backlog_kind, backlog_id, backlog_url),
            ccd_id,
            github_issue_number,
            session_id,
            worktree,
            branch,
        });
    }
    Ok(Some(assignments))
}

fn open_dispatch_db(path: &Path) -> Result<Connection> {
    if let Some(parent) = path.parent() {
        fs::create_dir_all(parent)
            .with_context(|| format!("failed to create {}", parent.display()))?;
    }
    let conn =
        Connection::open(path).with_context(|| format!("open dispatch db: {}", path.display()))?;
    conn.execute_batch("PRAGMA journal_mode=WAL; PRAGMA foreign_keys=ON;")?;
    migrate_dispatch_db(&conn, path)?;
    Ok(conn)
}

fn migrate_dispatch_db(conn: &Connection, path: &Path) -> Result<()> {
    let version: u32 = conn.pragma_query_value(None, "user_version", |row| row.get(0))?;
    if version == EXTENSION_DISPATCH_DB_SCHEMA_VERSION {
        return Ok(());
    }
    if version > EXTENSION_DISPATCH_DB_SCHEMA_VERSION {
        bail!(
            "backlog dispatch db schema version {} is newer than supported ({}) at {}; upgrade the ccd CLI",
            version,
            EXTENSION_DISPATCH_DB_SCHEMA_VERSION,
            path.display()
        );
    }
    if version == 0 {
        conn.execute_batch(EXTENSION_DISPATCH_DB_SCHEMA)?;
        conn.pragma_update(None, "user_version", EXTENSION_DISPATCH_DB_SCHEMA_VERSION)?;
        return Ok(());
    }

    bail!(
        "unsupported backlog dispatch db schema version {} at {}; delete or migrate the DB before retrying",
        version,
        path.display()
    )
}

fn assignment_backlog_columns(
    assignment: &DispatchAssignment,
) -> (Option<&str>, Option<&str>, Option<&str>, String) {
    let backlog_ref = assignment
        .backlog_ref
        .as_ref()
        .filter(|backlog_ref| !backlog_ref.is_empty());
    (
        backlog_ref.map(|backlog_ref| backlog_ref.provider.as_str()),
        backlog_ref.map(|backlog_ref| backlog_ref.kind.as_str()),
        backlog_ref.map(|backlog_ref| backlog_ref.id.as_str()),
        backlog_ref
            .map(|backlog_ref| backlog_ref.url.clone())
            .unwrap_or_default(),
    )
}

fn build_backlog_ref(
    provider: Option<String>,
    kind: Option<String>,
    id: Option<String>,
    url: String,
) -> Option<BacklogRef> {
    let provider = provider.filter(|value| !value.is_empty())?;
    let kind = kind.filter(|value| !value.is_empty())?;
    let id = id.filter(|value| !value.is_empty())?;
    Some(BacklogRef {
        provider,
        kind,
        id,
        url,
    })
}

fn hydrate_assignments_from_cache(
    assignments: &mut [DispatchAssignment],
    cache: &GitHubBacklogCache,
) -> bool {
    let mut changed = false;

    for assignment in assignments {
        let Some(item) = cache
            .items
            .iter()
            .find(|item| assignment_matches_item(assignment, item))
        else {
            continue;
        };

        if assignment
            .backlog_ref
            .as_ref()
            .map(BacklogRef::is_empty)
            .unwrap_or(true)
            && !item.backlog_ref.is_empty()
        {
            assignment.backlog_ref = Some(item.backlog_ref.clone());
            changed = true;
        }
        if assignment.github_issue_number == 0 && item.github_issue_number != 0 {
            assignment.github_issue_number = item.github_issue_number;
            changed = true;
        }
        if assignment.ccd_id == 0 && item.ccd_id != 0 {
            assignment.ccd_id = item.ccd_id;
            changed = true;
        }
    }

    changed
}

fn view_for_assignment(
    assignment: &DispatchAssignment,
    cache: Option<&GitHubBacklogCache>,
) -> LocalAssignmentView {
    let matched_item = cache.and_then(|items| {
        items
            .items
            .iter()
            .find(|item| assignment_matches_item(assignment, item))
    });
    let title = matched_item
        .map(|item| backlog::display_title(&item.title))
        .unwrap_or_else(|| {
            if assignment.ccd_id != 0 {
                format!("ccd#{}", assignment.ccd_id)
            } else if assignment.github_issue_number != 0 {
                format!("GH#{}", assignment.github_issue_number)
            } else if let Some(backlog_ref) = assignment
                .backlog_ref
                .as_ref()
                .filter(|backlog_ref| !backlog_ref.is_empty())
            {
                backlog_ref.key()
            } else {
                "backlog item".to_owned()
            }
        });
    LocalAssignmentView {
        backlog_ref: matched_item
            .map(|item| item.backlog_ref.clone())
            .filter(|backlog_ref| !backlog_ref.is_empty())
            .or_else(|| {
                assignment
                    .backlog_ref
                    .clone()
                    .filter(|backlog_ref| !backlog_ref.is_empty())
            })
            .unwrap_or_default(),
        ccd_id: assignment.ccd_id,
        github_issue_number: matched_item
            .map(|item| item.github_issue_number)
            .unwrap_or(assignment.github_issue_number),
        title,
        session_id: assignment.session_id.clone(),
        branch: assignment.branch.clone(),
        worktree: assignment.worktree.clone(),
    }
}

fn claimed_ids(assignments: &[DispatchAssignment]) -> BTreeSet<u64> {
    assignments
        .iter()
        .filter_map(|assignment| (assignment.ccd_id != 0).then_some(assignment.ccd_id))
        .collect()
}

fn claimed_ref_keys(assignments: &[DispatchAssignment]) -> BTreeSet<String> {
    assignments
        .iter()
        .filter_map(|assignment| {
            assignment
                .backlog_ref
                .as_ref()
                .filter(|backlog_ref| !backlog_ref.is_empty())
                .map(BacklogRef::key)
        })
        .collect()
}

fn assignment_matches_item(
    assignment: &DispatchAssignment,
    item: &backlog::GitHubBacklogItem,
) -> bool {
    assignment
        .backlog_ref
        .as_ref()
        .filter(|backlog_ref| !backlog_ref.is_empty() && !item.backlog_ref.is_empty())
        .map(|backlog_ref| backlog_ref.key() == item.backlog_ref.key())
        .unwrap_or(false)
        || (assignment.github_issue_number != 0
            && item.backlog_ref.provider == "github-issues"
            && item.github_issue_number == assignment.github_issue_number)
        || (assignment.ccd_id != 0 && item.ccd_id == assignment.ccd_id)
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::paths::state::ExtensionDispatchStatePaths;

    fn dispatch_paths_primary_only(path: &Path) -> ExtensionDispatchStatePaths {
        ExtensionDispatchStatePaths::new(path.to_path_buf())
    }

    fn write_dispatch_assignments(path: &Path, assignments: &[DispatchAssignment]) {
        write_dispatch_state(path, assignments).unwrap();
    }

    fn read_dispatch_assignments(path: &Path) -> Vec<DispatchAssignment> {
        read_dispatch_db(path).unwrap().unwrap_or_default()
    }

    #[test]
    fn load_claimed_ids_extracts_ids_from_private_dispatch_db() {
        let dir = tempfile::tempdir().unwrap();
        let dispatch_path = dir.path().join("dispatch-state.db");
        write_dispatch_assignments(
            &dispatch_path,
            &[
                DispatchAssignment {
                    backlog_ref: None,
                    ccd_id: 42,
                    github_issue_number: 0,
                    session_id: "ses_1".to_owned(),
                    worktree: "repo".to_owned(),
                    branch: Some("session/foo".to_owned()),
                },
                DispatchAssignment {
                    backlog_ref: None,
                    ccd_id: 99,
                    github_issue_number: 0,
                    session_id: "ses_2".to_owned(),
                    worktree: "repo".to_owned(),
                    branch: Some("session/bar".to_owned()),
                },
            ],
        );

        let ids = load_claimed_ids(&dispatch_paths_primary_only(&dispatch_path)).unwrap();
        assert_eq!(ids, BTreeSet::from([42, 99]));
    }

    #[test]
    fn read_dispatch_db_fails_closed_on_negative_ccd_id() {
        let dir = tempfile::tempdir().unwrap();
        let dispatch_path = dir.path().join("extensions/backlog/dispatch-state.db");
        let conn = open_dispatch_db(&dispatch_path).unwrap();
        conn.execute(
            "INSERT INTO assignments (
                backlog_provider, backlog_kind, backlog_id, backlog_url,
                ccd_id, github_issue_number, session_id, worktree, branch
            ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9)",
            rusqlite::params![
                Option::<String>::None,
                Option::<String>::None,
                Option::<String>::None,
                "",
                -1_i64,
                0_i64,
                "ses_bad",
                "repo",
                Option::<String>::None,
            ],
        )
        .unwrap();

        let err = read_dispatch_db(&dispatch_path).unwrap_err();
        assert!(err.to_string().contains("invalid ccd_id value `-1`"));
    }

    #[test]
    fn adopt_unsessioned_entries_promotes_all_db_entries() {
        let dir = tempfile::tempdir().unwrap();
        let dispatch_path = dir.path().join("extensions/backlog/dispatch-state.db");
        write_dispatch_assignments(
            &dispatch_path,
            &[
                DispatchAssignment {
                    backlog_ref: None,
                    ccd_id: 42,
                    github_issue_number: 0,
                    session_id: String::new(),
                    worktree: "repo".to_owned(),
                    branch: Some("main".to_owned()),
                },
                DispatchAssignment {
                    backlog_ref: None,
                    ccd_id: 99,
                    github_issue_number: 0,
                    session_id: "ses_EXISTING".to_owned(),
                    worktree: "repo".to_owned(),
                    branch: Some("feature".to_owned()),
                },
            ],
        );

        let dispatch_paths = dispatch_paths_primary_only(&dispatch_path);
        let adopted = adopt_unsessioned_entries_for_paths(&dispatch_paths, "ses_NEW").unwrap();
        assert_eq!(adopted.len(), 1);
        assert_eq!(adopted[0].ccd_id, 42);
        assert_eq!(adopted[0].session_id, "ses_NEW");

        let assignments = read_dispatch_assignments(&dispatch_path);
        assert_eq!(assignments.len(), 2);
        assert!(assignments
            .iter()
            .any(|assignment| assignment.session_id == "ses_NEW"));
        assert!(assignments
            .iter()
            .any(|assignment| assignment.session_id == "ses_EXISTING"));
    }

    #[test]
    fn remove_session_entries_clears_matching_session() {
        let dir = tempfile::tempdir().unwrap();
        let dispatch_path = dir.path().join("dispatch-state.db");
        write_dispatch_assignments(
            &dispatch_path,
            &[
                DispatchAssignment {
                    backlog_ref: None,
                    ccd_id: 42,
                    github_issue_number: 0,
                    session_id: "ses_OLD".to_owned(),
                    worktree: "repo".to_owned(),
                    branch: Some("main".to_owned()),
                },
                DispatchAssignment {
                    backlog_ref: None,
                    ccd_id: 99,
                    github_issue_number: 0,
                    session_id: "ses_KEEP".to_owned(),
                    worktree: "repo".to_owned(),
                    branch: Some("feature".to_owned()),
                },
            ],
        );

        let dispatch_paths = ExtensionDispatchStatePaths::new(dispatch_path.clone());
        remove_session_entries_for_paths(&dispatch_paths, "ses_OLD").unwrap();

        let assignments = read_dispatch_assignments(&dispatch_path);
        assert_eq!(assignments.len(), 1);
        assert_eq!(assignments[0].session_id, "ses_KEEP");
    }
}